Oil shortage determining system

Abstract

In a vehicle including a first MG serving as a driving source, a power transmission mechanism configured to transmit power of the first MG to a drive wheel, and an oil circulation mechanism for cooling the power transmission mechanism and the first MG, it is determined that oil is short when a temperature of the first MG is higher than a temperature of the oil and a difference between the temperature of the first MG and the temperature of the oil is greater than a prescribed value.

What is claimed is: 
     
       1. An oil shortage determining system comprising:
 a motor serving as a driving source of a vehicle; 
 a power transmission mechanism configured to transmit power of the motor to a drive wheel of the vehicle; 
 an oil circulation mechanism configured to circulate oil for cooling the power transmission mechanism and the motor; 
 a first temperature sensor configured to detect a temperature of the motor; 
 a second temperature sensor configured to detect a temperature of the oil; and 
 a determining device configured to determine whether there is a shortage of the oil, wherein: 
 the determining device is configured to execute
 an acquisition process of acquiring a temperature of the motor and a temperature of the oil, and 
 a determining process of determining whether there is a shortage of the oil based on the temperature of the motor and the temperature of the oil; 
 
 in the determining process, the determining device is configured to determine that the oil is short when the temperature of the motor is higher than the temperature of the oil and a difference between the temperature of the motor and the temperature of the oil is greater than a predetermined prescribed value; 
 where a duration from when an ignition switch of the vehicle is turned on to when the ignition switch is turned off is one trip; 
 the determining device is configured to, when the temperature of the oil to be acquired in the initial acquisition process of each trip is lower than or equal to a predetermined threshold, prohibit a determination that the oil is short in the determining process until the trip ends; and 
 the determining device is configured to, when the temperature of the oil to be acquired in the initial acquisition process of each trip is higher than the threshold, execute the determining process without prohibiting a determination that the oil is short until the trip ends. 
 
     
     
       2. The oil shortage determining system according to  claim 1 , wherein:
 the determining device includes an internal device provided in a target vehicle that is a vehicle set as a target for determination as to whether there is a shortage of the oil, and an external device provided outside the target vehicle; 
 the external device is capable of wirelessly communicating with the internal device and stores the prescribed value for each of a plurality of vehicle types; 
 the internal device is configured to execute the acquisition process and a transmission process of transmitting information on the temperature of the motor and the temperature of the oil, acquired in the acquisition process, to the external device together with vehicle type information of the target vehicle; 
 the external device is configured to execute a receiving process of receiving the information transmitted in the transmission process, an identification process of identifying the prescribed value associated with the vehicle type information received in the receiving process, and the determining process; and 
 in the determining process, the external device is configure to acquire a difference between the temperature of the motor and the temperature of the oil based on the information acquired in the receiving process, and compare the acquired difference with the prescribed value identified in the identification process. 
 
     
     
       3. The oil shortage determining system according to  claim 2 , wherein:
 the internal device stores a maximum value in historical data of a difference between the temperature of the motor and the temperature of the oil, acquired in the acquisition process; and 
 the internal device is configured to, only when a difference between a latest temperature of the motor and a latest temperature of the oil is greater than the maximum value, transmit the latest temperature of the motor and the latest temperature of the oil in the transmission process. 
 
     
     
       4. The oil shortage determining system according to  claim 2 , wherein the external device is configured to, when the external device determines in the determining process that the oil is short, execute a notification process of providing notification of a shortage of the oil to the internal device. 
     
     
       5. An oil shortage determining system comprising:
 a motor serving as a driving source of a vehicle; 
 a power transmission mechanism configured to transmit power of the motor to a drive wheel of the vehicle; 
 an oil circulation mechanism configured to circulate oil for cooling the power transmission mechanism and the motor; 
 a first temperature sensor configured to detect a temperature of the motor; 
 a second temperature sensor configured to detect a temperature of the oil; and 
 a determining device configured to determine whether there is a shortage of the oil, wherein: 
 the determining device is configured to execute
 an acquisition process of acquiring a temperature of the motor and a temperature of the oil, and 
 a determining process of determining whether there is a shortage of the oil based on the temperature of the motor and the temperature of the oil; 
 
 in the determining process, the determining device is configured to determine that the oil is short when the temperature of the motor is higher than the temperature of the oil and a difference between the temperature of the motor and the temperature of the oil is greater than a predetermined prescribed value; 
 the determining device includes an internal device provided in a target vehicle that is a vehicle set as a target for determination as to whether there is a shortage of the oil, and an external device provided outside the target vehicle; 
 the external device is capable of wirelessly communicating with the internal device and stores the prescribed value for each of a plurality of vehicle types; 
 the internal device is configured to execute the acquisition process and a transmission process of transmitting information on the temperature of the motor and the temperature of the oil, acquired in the acquisition process, to the external device together with vehicle type information of the target vehicle; 
 the external device is configured to execute a receiving process of receiving the information transmitted in the transmission process, an identification process of identifying the prescribed value associated with the vehicle type information received in the receiving process, and the determining process; and 
 in the determining process, the external device is configured to acquire a difference between the temperature of the motor and the temperature of the oil based on the information acquired in the receiving process, and compare the acquired difference with the prescribed value identified in the identification process. 
 
     
     
       6. The oil shortage determining system according to  claim 5 , wherein:
 the internal device stores a maximum value in historical data of a difference between the temperature of the motor and the temperature of the oil, acquired in the acquisition process; and 
 the internal device is configured to, only when a difference between a latest temperature of the motor and a latest temperature of the oil is greater than the maximum value, transmit the latest temperature of the motor and the latest temperature of the oil in the transmission process. 
 
     
     
       7. The oil shortage determining system according to  claim 5 , wherein the external device is configured to, when the external device determines in the determining process that the oil is short, execute a notification process of providing notification of a shortage of the oil to the internal device.